1. Field of the Invention
The present invention relates to a time-stable sterile pharmaceutical composition comprising piperacillin sodium and tazobactam sodium mixed with sodium bicarbonate, this composition being soluble in water to give an injectable sterile solution highly stable with time.
2. Discussion of the Background
EP 1759697A and the corresponding application published under No. 2007/0054889A1 in the name of the present applicants describe the preparation of a stable, sterile homogeneous mixture of piperacillin sodium and tazobactam sodium of substantially the same density, which is soluble in water to give a reconstituted solution with a pH of about 5.6.
During tests carried out after filing EP1759697A it was however observed that the said sterile solution can give rise to a precipitate or to turbidity some minutes after its preparation. This quantitatively very limited precipitate, or possible turbidity, renders the solution unsuitable for clinical use, also in consideration of the fact that administration of the drug by injection does not always immediately follow the preparation of the injectable solution, but several minutes can pass between the solution preparation and its administration to the patient.